Materials for Constructional Work

TIMBER is stocked at the timber yards in two forms; sazwn and prepared. Prepared timber is planed on some or all sides or edges, according to its intended uses. The planing of prepared timber naturally reduces it to something less than the nominal sizes by which it is sold. For example, a one-inch board in the rough, that is sawn, but not planed, will be approximately an inch in thickness. But ‘inch’ board planed on both sides and both edges will lose about an eighth of an inch in thickness and in width. If the worker requires planed boards that will measure an inch after planing, he should state this together with the type of timber required when ordering them, and thicker timber will be put through the planing machine so that the finished thickness is, in fact, one inch.

Quartering

This is timber with such sectional measurements as 2 in. x 2 in., 3 in. x 2 in., 3 in. x 3 in., 4in. X 2 in., and 4 in. x 4in., and when sold sawn will measure approximately these dimensions. If bought to these nominal sizes as ‘prepared’, each section will lose in breadth and thickness as explained above.

Plain-edge board, bought planed will be less than the nominal width and thickness, as previously mentioned. A tongued and grooved board, when fitted to another, will be less than its nominal width by the depth of the groove into which the tongue fits. Grooved boards are jointed by separate slips or tongues, sometimes called feathers, inserted into the groove of one board after glueing or painting, and then this board is pushed up to the adjoining board so that the tongue also fits into that groove. These slips must be free from defects.

Matchboard, or matching, loses in width by the same amount as tongued and grooved board, but is planed on one face only. For substantial work nothing less than ’m. matching should be used, which in effect is jjin. Thick. But if it is required merely for covering in the back of a piece of kitchen equipment, then -½ in. matching will serve. Apart from its fragility, thin matchboard is often found to be defective at the tongues or grooves, there being so little thickness at these parts. Moreover, the parts in question are apt to break away when the boards are being fitted together unless great care is taken.

Weatherboard, in the cheaper grades is nothing more than feather-edge board, two boards being cut obliquely from, say, a ¾ in. board so that each tapers away at one edge. At the thicker edge the boards will be less than ¾ in. by the material taken out by the saw blade. Here again, avoid the thinnest stuff, and take nothing thinner than -½ in. This type of board is used for fences, and thicker measurements will do for the outside covering of wooden sheds and similar outbuildings. But for any worth-while job where the boards are to be laid horizontally rebated weatherboards should be used. These are made with a rebate on the under side of the thick edge of each board, this rebated part fitting over the narrower edge of the next board below. Various grades are sold, cut from different qualities of timber. Generally, on outdoor work, it is almost a waste of money to use the cheaper or thinner kinds of board.

A still better material is moulded and rebated weatherboard which is shaped at the thin, or top, part as well as being rebated at the thick part. It looks nice and in fact has an altogether superior appearance, besides being far more durable and capable of more secure fixing. This type of board would be used for a good summer house, a sun-room, or for the timber sides of a veranda.

Battens, which are small boards measuring, say, 2 in.x 1 in., 2 in. x ¾ in., and so on, are useful for a variety of household jobs. Besides these, it is possible to get timber of 1 in. x 1 in. section,1 ½ in. x 1 ½., 1 in. x ½ in., and others. Quartering is also sold measuring 2 in. x 1 ½ in. in section, but is too slight for most constructional jobs where such a material is normally used. Some of these slightsections are found mostly in the cheap portable buildings much advertised in gardening and other journals. They are worth what they cost, and the purchaser has only himself to blame if he expects to get a five-pound article for half that price. Incidentally this demonstrates the big saving possible when the handyman builds his own sheds, etc. Either he can spend the same amount on materials alone, giving his own labour and getting a first-class article, or he can actually save money by making the same shed as advertised and saving the labour cost.

Roofing Materials

Corrugated steel sheets, galvanized, are made in various thicknesses, but nothing thinner than 24 gauge should be used for roofs; 22 gauge is much preferable for durability. The sheeting is made with 3 in. and 5 in. corrugations but the smaller one is generally used. Various stock lengths are kept, with a standard width of 2ft. 3in. This material cannot be painted satisfactorily until it has been weathered by exposure for six months or so.

Corrugated asbestos-cement sheets are an alternative material, better in appearance than steel but somewhat brittle. If put on carefully, and not subjected afterwards to blows or shocks, it is very lasting. Both these materials are fixed by nailing or screwing to roof timbers. Holes in the steel sheeting are made by punching with a sharp punch over a block of wood, but asbestos-cement must be drilled carefully with a twist drill in a carpenter’s brace or hand drill . A curved washer is put between the top of the nail or screw and the sheeting. Holes are made in the ‘hills’ of the sheeting, not in the ‘valleys’. Both sorts of corrugated sheet can be used for the sides of sheds, etc.

Flat asbestos-cement sheets are used for lining the walls of outbuildings, and sometimes for the outside. The sheets are fixed edge to edge, with a small gap between. The joints are then covered by a strip of1 ½ in. x ¾ in. deal nailed through so that the nails enter the underneath studding in the gap between the asbestos-cement sheets. Holes in asbestos-cement sheets should always be drilled.

Wallboards, in many different materials, are sold for lining the in-sides of buildings, making partitions, etc., and some types also will do for use outside. Special types are made for keeping in warmth and keeping out noise. These are softer and more ‘open’ in texture than the harder boards intended for other jobs.

Bricks, Cement, Lime and Sand

The common pinkish-coloured bricks are used for all work where the surface is protected from the weather, as by roughcast or cement rendering. Harder and better quality bricks are needed for exposed positions. The best in appearance and durability are the facing bricks, used for outside walls. Another good quality is the stock brick, yellowish in colour. Bricks used for paving, or for doorsteps, etc. must be of a hard type (such as Blue Staffords or Dutch Clinkers), and the worker should ask for them specifically when purchasing. Engineering bricks, hardest of all, are blueish in colour, and somewhat more costly. Bull nose shapes (with rounded edge) can be used for the finishing course of steps, and many other ‘specials’ are to be had for other positions where a shaped finish is wanted.

Roofing tiles including ridge and hip coverings are made in various shades and qualities. Slates are sold in many stock sizes. Except on porches or low roofs, the repair or replacement in both cses is hardly a job for the novice, who may do more damage to adjoining roofing than he originally set out to remedy.

Portland cement can be purchased in 7 lb. Or 14 lb. Bags, or larger quantities. Purchase no more than is necessary for immediate work, as it is troublesome to keep dry and may deteriorate if kept for some months. For extensive work cement should be bought in 1-cwt. Bags. It is seldom advisable to use pure cement without sand, for this usually cracks after a short time. Mix the cement with sharp sand, that is, sand from which all earthy matter has been washed out. Washed sand sold by the builders’ merchant is of this type; sea sand is not generally satisfactory. The proportion of sand to cement varies with different sorts of jobs but a good general mixture is 1 of cement to 3 of sand. Make a dry mixture of cement and sand and then mix it twice after wetting. Avoid adding too much water; the mortar, after mixing, should be plastic, but not fluid.

Lime mortar is a substitute for Portland cement mortar when great strength is not needed, but it is sometimes strengthened with a small amount of Portland cement. Lime, after slaking with water sprinkled on to it from the rose of a watering can, is mixed with sand to form the mortar. Lime can be bought in small lots or in hundred- weight bags. It needs the same care as cement, so far as protection from moisture is concerned, and care should be taken to keep it from the eyes and away from clothing.

In all jobs which involve the use of cement, the parts to be dealt with must be well wetted before starting; for it is obvious that porous sub- stances will suck up moisture rapidly, and if the brickwork of walls etc. is very dry it may absorb too much moisture from the cement and destroy or weaken its adhesive quality. Bricks, floor tiles, and such like, should be dipped in a pail of water before laying.

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